Intravenous fluid use after cardiac surgery: a multicentre, prospective, observational study

Background: The optimal strategy for fluid replacement after major surgery remains unclear and there is considerable interest in the investigation of more restrictive fluid regimens. Objective: We aimed to establish current practice of fluid administration to patients after cardiac surgery. Design, setting and participants: A multicentre, prospective observational study, over an 8-week period, of consecutive patients admitted to five intensive care units in New Zealand and Australia. Main outcome measures: We collected patient demographic data and details of fluid boluses and all other intravenous (IV) fluids administered in the first 24 hours after ICU admission. Results: We included 235 patients, and 1226 fluid boluses with an average volume of 504 mL/bolus were administered. The median total fluid given for volume expansion in the first 24 hours was 2250 mL (interquartile range [IQR], 1250?3500 mL) from a median total IV fluid intake of 4493 mL/patient (IQR, 2842?5498 mL). The decision to administer a fluid bolus was made 40 of the time by nursing staff, 45 by an ICU resident and 12 by an ICU specialist. The most common reason for fluid administration was hypotension (65 ), and crystalloid fluid was used for 65 of the boluses. Conclusions: We showed that fluid boluses are responsible for a large proportion of the positive fluid balance seen in patients after cardiac surgery. These data justify further study to evaluate whether modification of fluid bolus administration can improve patient outcomes.